Offer your clients a free consultation.
These consultations should be schedule on a semi-yearly or yearly basis. If you have had a client for 5 years and have not contacted them once in those 5 years now is the time to do so.
Send them cards for special events, ie birthday cards, holiday cards, miss you cards.
Make sure you keep track of your clients birthdays or other special days. If in the midst of a conversation with your client, your client states they have a new job, send them a card. Any easy way to keep track of your clients and their special information is to use a web based CRM or contact management software.
Make sure every contact you have with them is professional and courteous.
Remember your clients can refer other potential clients to you. Every communication with your client should be professional and courteous. When answering the phone always answer as if it is your first phone call of the day. Your voice should sound fresh and energetic. Your client should not be able to tell by the sound of your voice that you are stressed out or just had a bad meeting.
Under promise but over deliver.
When your client makes a request deliver beyond their wildest dreams. For example, if you client needs paperwork faxed by next Friday, you state that you will have it there by their deadline, but you actually fax it a couple of days before.
Answer emails promptly.
Let your customers know that their emails will be answered within a 24 hour period. If you do not work on Sundays or are away from your office you should place an out of office reply in your email and when they can expect a response from you. PLEASE REMEMBER TO TURN OFF YOUR OUT OF OFFICE REPLY WHEN YOU RETURN TO THE OFFICE.
When they have a complaint, listen to the problem provide a solution.
When your customer has a complaint, listen. Make sure you understand the problem before you give the customer a solution. If the problem is your fault take accountability and offer a solution.